The present invention generally relates to pharmaceutically active compositions and methods of making the same.
The present invention relates to a process for the preparation of solid oral dosage forms such as tablets, capsules, granules,etc comprising as active ingredient 4-amino-1-hydroxybutylidene-1,1-biphosphonic acid or one of its pharmaceutical acceptable salts in particular the sodium or potassium salts. (Said acid will be called hereinafter xe2x80x9cAlendronic acidxe2x80x9d. It comprises unless otherwise stated the free acid or one of its pharmaceutically acceptable salts.)
Alendronic acid is a known compound. It serves for the treatment of diseases abnormal (ectopic) depositions of calcium salts and in the reduction of bone resorption. As such diseases there may be mentioned, inter alia, osteoporosis, menopausal osteoporosis, osteodystrophy, Paget""s disease, myositis ossificans, Bechterew""s disease, malignant hypercalcemia, metastatic bone disease, periodontal disease, cholelithiasis, nephrolithiasis, urolithiasis, urinary calculus, sclerosis, arthritis, bursitis, neuritis and tetany.
There are known various processes for the preparation of tablets comprising as active ingredient alendronic acid, for example, from the following patent Specifications:
1. WO/94/12200 which describes and claims the preparation of such tablets by a dry method;
2. WO/95/29679 which describes and claims the preparation of such tablets by wet granulation; and
3. WO/95/08331 which describes and claims the preparation of such tablets coated by an enteric coat.
In the wet granulation process described and claimed in WO/95/29679 all ingredients including the Alendronic acid are admixed and the mixture is wetted with water, an organic solvent or a solution of said solvent in water.
However,the tablets obtained by said processes are not entirely satisfactory in particular the processes described in 1. and 2. The tablets obtained by said processes irritate to an undesired extent the digestive system; and the absorption of the alendronic acid is not entirely satisfactory.
It has thus been desirable to develop a process which provides tablets which cause less irritation to the digestive system; and in which the absorption of the alendronic acid is improved.
The present invention thus consists in a process for the preparation of tablets or capsules comprising as active ingredient alendronic acid (as herein defined) comprising:
1. forming a powder blend of inert pharmaceutically acceptable excipients;
2. granulation of the powder with a suitable aqueous solution containing alendronic acid;
3. drying the granules obtained; and, if desired,
4. either compressing the granulate obtained into tablets;
or filling same into capsules.
In an optional step a binder, is added to the powder blend prepared in step 1 and/or to the wetting solution obtained in step 2. As binder, if any, there may be used, e.g. polyvinylpyrrolidone (PVP), hydroxypropylmethylcellulose (HPMC), pregelatinized starch, etc.
The excipients used in step 1 are carriers, e.g. microcrystalline cellulose, lactose, calcium hydrogen phosphate, calcium triphosphate, etc. advantageously admixed with disintegrants, e.g. carboxymethylcellulose sodium (croscarmellose sodium), sodium carboxymethylstarch (Primojel(copyright)) , crospovidone, etc. There may be used one or more carriers and one or more disintegrants.
The aqueous solution used in step 2 is preferably prepared by admixing the alendronic acid with an alkali advantageously NaOH, KOH, NH4OH, etc, in a ratio of 1 : 1-4 moles, preferably 1 : 1-3 moles.
However, said aqueous solution may be prepared also by other suitable methods, e.g. by admixing the alendronic acid with a salt of a weak acid and a strong base; or by admixing the alendronic acid with any suitable water soluble salt enabling to solubilize the alendronic acid. All the various reagents should be pharmaceutically acceptable.
The method according to the present invention differs from that of WO/95/29679 as specified above in that the alendronic acid is dissolved in water and said solution is used for the granulation of the powder blend.
The ratio between the power blend obtained in step 1 and the solution used in step 2 is preferably 1 : 0.2 to 1 : 4. In case that the amount of the solution used in step 2 is large the addition of the solution to the powder is done in portions, and the granules are dried after the addition of each portion.
The drying step is suitably performed in a tray oven, preferably in a fluid bed advantageously at an inlet temperature of about 50xc2x0 C.
The dried granulates obtained are preferably sieved, advantageously with a mesh 16 sieve.
The dried granules obtained are advantageously, preferably after sieving, admixed with lubricants and/or with disintegrants. Some more of the carriers used in step 1 may be added to the dry granules. Said disintegrants may be the same as those used in step 1. The lubricants may be, e.g. magnesium stearate, calcium stearate, sodium lauryl sulfate, etc. The quantity of the various lubricants and/or the disintegrants is preferably 0.1 to 5% of the granule weight.
All said carriers, disintegrants and lubricants should be pharmaceutically acceptable.
The present invention also consists in a tablet prepared by the method according to the present invention. Said tablet weighs, e.g. 40-1200 mg and comprises, e.g. 1-25%, advantageously 2-15% of the alendronic acid.
The present invention also consists in a capsule comprising granules as prepared by the process according to the present invention.
The tablets and the capsules may be entero-coated by known conventional techniques with solutions or suspensions of suitable polymers used for entero-coating, e.g. of cellulose acetate phthalate (CAP), hydroxypropyl methylcellulose phthalate (HPMCP), Eudragit L(copyright), etc. Said solutions and suspensions may comprise additional compounds used for film coating.
A subcoat formed from an inert water soluble polymer, e.g. hydroxypropylmethylcellulose (HPMC), hydroxypropylcellulose (HPC), povidone (PVP), etc. may be applied between the tablets and/or capsules and the entero-coat outer layer.